<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>微信登陆</title>
</head>
<body>
    <script>
        function getUrlParams(key) {
            var args = {};
            var pairs = location.search.substring(1).split('&');
            for (var i = 0; i < pairs.length; i++) {
                var pos = pairs[i].indexOf('=');
                if (pos === -1) {
                    continue;
                }
                args[pairs[i].substring(0, pos)] = decodeURIComponent(pairs[i].substring(pos + 1));
            }
            return args[key];
        }
        function appendParams(params, url) {
            var baseWithSearch = url.split('#')[0];
            var hash = url.split('#')[1];
            for (var i = 0; i < params.length; i++) {
                if (params[i].value !== undefined) {
                    var newParam = params[i].key + "=" + params[i].value;
                    if (baseWithSearch.indexOf('?') > 0) {
                        var oldParamReg = new RegExp(params[i].key + '=[-\\w]{0,40}', 'g');
                        if (oldParamReg.test(baseWithSearch)) {
                            baseWithSearch = baseWithSearch.replace(oldParamReg, newParam);
                        } else {
                            baseWithSearch += "&" + newParam;
                        }
                    } else {
                        baseWithSearch += "?" + newParam;
                    }
                }
            }
            if (hash) {
                url = baseWithSearch + '#' + hash;
            } else {
                url = baseWithSearch;
            }
            return url;
        }
        var code = getUrlParams('code');
        var appId = getUrlParams('appid');
        var scope = getUrlParams('scope') || 'snsapi_base';
        var state = getUrlParams('state');
        var redirectUrl;
        if (!code) {
        
        	document.getElementById("code").innerText = code;
            redirectUrl = appendParams([{
                key: 'appid',
                value: appId
            }, {
                key: 'redirect_uri',
                value: encodeURIComponent(location.href)
            }, {
                key: 'response_type',
                value: 'code'
            }, {
                key: 'scope',
                value: scope
            }, {
                key: 'state',
                value: state
            }], 'https://open.weixin.qq.com/connect/oauth2/authorize#wechat_redirect');
        } else {
            redirectUrl = appendParams([{key: 'code', value: code},{
                key: 'state',
                value: state
            }], getUrlParams('redirect_uri'));
        }
        location.href = redirectUrl;
    </script>
    <span id="code"></span>
    
</body>
</html>